Is it possible to trademark the symbol Pi, followed by a period?

Can the Greek letter, widely used in math, known as Pi, be eligible for trademark protection?

Well, an attorney from Long Island has threatened a business known as Zazzle with legal action if it does not cease and desist using the Greek letter followed by a period on its t-shirts.

The lawyer apparently represents Paul Ingrisano, who is identified as the owner of “Pi Productions Corp” of New York, which got a patent from the U.S. Patent and Trademark Office on the symbol Pi followed by a period. It sells designed t-shirts that include the symbol Pi followed by a period.

The cease and desist letter from Attorney Ronald Millet claims Zazzle has “unlawful use of PI trademark.” It mentions “monetary damages” and other kinds of “relief,” as well as attorney’s fees and court costs.

“It has been brought to our client’s attention that your business, Zazzle Com/AKA Zazzle Inc., has been using the mathematical symbol ‘pi,’ referred to herein as the ‘PI trademark,’ in association with the marketing or sale of your products or of products offered through your services,” Millet wrote in the letter sent to Zazzle. “We have evidence of your unlawful products to preserve as evidence. Accordingly, you are hereby directed to CEASE AND DESIST ALL COPYRIGHT INFRINGEMENT.”

Zazzle temporarily pulled all clothing that includes the symbol. On Friday, some of the Pi shirts were once again found at Zazzle – which is a custom t-shirt printing website, according to a report from Wired.

Among those who got his designed t-shirts pulled by Zazzle was Dave Lartigue. In a blog post, Lartigue explained that, “Pi is … the name given to the ratio of a circle’s diameter to its circumference. … This symbol is used in every mathematical text and paper involving this ratio, and has been since at least 1706. Of course, the Greeks [used] ... the symbol as a letter in their alphabet long before that…. And now someone’s claiming they’ve trademarked it and no one else can use it? That’s like trademarking the number three, or hell, the e in the design, which is another mathematical concept. It’s clearly absurd….”

“There is someone out there who has claimed copyright ownership of the symbol pi who is actively trying to shut down anyone who has used it,” added Jez Kemp, who also had his designed pulled by Zazzle, according to a blog post. “Print-on-demand websites are bombarded by these fraudulent claims every day, and most are rightly dismissed. But sites like Zazzle are so terrified of lawsuits, they often automate their content review process.”